Footwear closure systems typically use a lacing or similar fastener system to fasten the shoe around the foot. In the simplest form of a lacing system, the upper is split down its middle bisecting the area above the instep, and eyelets or hooks or fasteners are located along either side of the split (eyestays). A lace is passed through the eyelets and crisscrossed across the split from the bottom of the split nearer the toe to the top of the split nearer the ankle. By pulling on the free ends of the lace, the split portions of the upper are drawn toward one another and the shoe is tightened around the foot. A tongue is generally provided underneath the split of the upper to provide a fully enclosed environment for the foot, and the eyestays pull together over the top of the tongue or any material lying between the eyestays. The tongue is frequently padded to protect the wearers' feet from the discomfort of the pressure of the laces.
Specialty outdoor and waterproof footwear construction typically incorporates a central tongue that lies underneath the laces when the closure system is drawn tight, with gussets connecting the sides of the tongue to each side of the upper in the area of the split. The gussets provide a continuous surface between the upper and the tongue, preventing liquids or debris from getting inside the shoe or boot. The gussets are also configured to provide an opening large enough to permit entry of the foot when the closure system is open. In this situation, the gusset is widest near the exposed end of the tongue nearest the ankle. When the closure system is tightened, the gusset material folds against the foot in the area on each side of the tongue generally next to or underneath the eyestays.
Waterproof footwear conventionally has a waterproof fabric liner provided in the interior of the footwear, contacting the foot. Waterproof and breathable fabrics are commonly provided in a simple construction involving a sock-like configuration shaped to fit within a shoe upper and attached to the top and bottom portions of the upper. The liner construction commonly follows the pattern of the boot or shoe upper in the region of the closure system, the liner having gussets matching the gussets in the area of the footwear closure to provide an opening for insertion of the foot. This construction allows the liner to form a continuous barrier to water from outside the shoe, thereby keeping the wearer's feet dry. The liner may have an integral, sock-like configuration with a lower portion generally following the configuration of the insole, or the liner may be attached to a separate component, such as a water impermeable plate or liner, that extends for the length of the interior of the footwear and is shaped to match the insole.
U.S. Pat. No. 4,599,810, for example, discloses an inner liner constructed of a material that is impervious to water but previous to perspiration vapors. The liner has a sock-like configuration, with fold portions similar to fold portions at the front of the shoe to allow the wearer to insert and remove his foot. The liner may be secured to the upper only in an area proximate the top opening.
When the closure system of this type is drawn tight, the gussets and liner between the eyestays fold or bunch as a result of the accumulation of material in the reduced distance between the eyestays. If the material is folded against the foot, the additional pressure caused by the accumulation of folded material under the tightened laces can be uncomfortable. Since the instep at the top of the foot is an especially sensitive part of the foot, where many blood vessels and tendons are near the surface, any points of pressure on the instep can cause discomfort. Additionally, since the upper must flex in the region of the instep to accommodate the hinge action of the ankle and foot, the potential to cause pain from the folded gusset and liner material is high.
In an effort to reduce the amount of folded material beneath the eyestays and next to the foot, some footwear designs limit the amount of excess fabric in the area of the instep. This compensation has the effect of reducing the size of the opening for insertion of the foot when the closure system is open. Outdoor footwear having a sock-like stretch booty constructed, for example, from Neoprene, is an example of this type of design. In this design, the stretch booty is attached to the inner surface of the-upper and underlies the closure system. In some designs, the stretch booty is not attached to the upper at the top of the footwear. When the closure system is drawn tight, there is little bunching of the stretch booty. Footwear having a stretch booty design is generally comfortable, but it can be difficult to insert and remove the foot, as a result of the relatively small opening for insertion of the foot. If the opening is large enough to comfortably accommodate insertion of the foot, the footwear is generally prone to having debris enter the interior of the boot at the top of the booty.
Waterproof footwear is highly desirable. U.S. Pat. No. 4,599,810 is one example of a water impervious liner. Another system for providing a waterproof environment inside footwear involves using a separate, waterproof sock or liner that is worn between the foot and the footwear. Such waterproof liners are versatile because a single pair may be used with a variety of footwear. Partially stretchable waterproof socks have been developed in an effort to reduce the amount of excess fabric and provide a sock that conforms closely to the foot. Nonetheless, the separate waterproof liners, even those made partially or wholly of stretchable fabric, still tend to bunch when the footwear closure system is drawn tight. A liner that is integral with the footwear generally provides a better fit, less excess fabric and greater comfort.
There thus remains a need in the art for footwear having a construction that permits easy entry and removal of a foot, and is comfortable in the area of the instep when the closure system is closed. Such footwear having a waterproof, breathable liner is especially desirable. The present invention is directed to footwear of this type.